Geometrical instrument



March 26, 1940. J. k. BARNS QEOMETRICAL INSTRUMENT Filed March 4, 1939 2 Sheets-Sheet 1 In ventor .W E U March 26, 1940. J. K. BARNs 2,194,632

eEoMETRIcAL INSTRUMENT v Filed March 4, 19:59 2 Smets-snee*b 2 Inventor man.

orneys Patented Mar. 26, 1940 PATENT oFvFicE e y 2,194,632 l GEoMETRIoAL INSTRUMENT John K. Barns, Bement, Ill. A Application March 4,1939, seriaiNo. 259,913

l 2 Claims.

This invention relates to newand useful im-` provements in geometrical instruments and more particularly to a knock-down square. y

The principal object of the present invention is to provide a geometrical instrument in the form of a square of substantially large sizewhich can be usually knocked down to shorten the c same to facilitate its placement in a tool chest. Other objects and advantages of the invention will become apparent to the reader of the following specification. 4

In the drawings: e Figure 1 represents a fragmentary plan view of the square assembled. l

Figure 2 is a plan View of the angle section.

Figure 3 is a fragmentary plan View of the leg section.

Figure 4 is a section online 444' of vFigure 1.

Figure 5 is a section on line 5-5 of Figure l.

Figure 6 is a section on line 6-6 of Figure 2.A

Figure 'l is an elevational view of the rotary detent.

Figure 8 is a sectional View on line `8--8 of Figure 3. v l

Figure 9 is a sectional view on line 9-9 of Figure 3. e e

Referring to the drawings wherein like numerals designate like parts, it can be seen that the square consists of the sections A and B. The

section A is of right-angular construction and"l consists of the leg 5 and arm portion 6;

The arm 6 has graduations 6a and @belong` its inner and outer edges, while the leg 5 has graduations 5a along its outer edge and numerals 5h along its inner edge which are matchable with the numerals la on the leg extension l, `the l latter having graduations "lbwhich form a continuation of the graduations 5a and graduations l'c along its inner edge portion. The numerals 'la ofthe leg extension l form a continuation of the scale 'ld in conjunction with the numerals 5b of the leg 5. l

. The end portion of the leg extension 'l adjacent the section. A is reduced in width. As a matter of fact it is reduced to substantially half of its width and its reduced width matches the width of the leg 5, thus deningthe shoulder 8 in the leg extension l againstwhich the end 9 of the leg 5 can abut.

A reduced lug ill projects from the shoulder 8 and has itsouter end beveledas at I l and further formed with a transverse channel l2.

Thefadjacent end of the leg 5 is reduced in" 'as newis: l l

l. A geometrical instrument comprising a rest against the beveled wall l5, so that seating actionas shown in Figure 4 will take place.

A rotary detent I6 is provided in the free end of the reduced portion ofthe leg extension l. This is inthe form of a rivet having a winged head il and a kerf i8 for the reception of a screwdriver or other tool. The head Il can be disposed through the doubleA key hole'slot i9 `of the armv 6 adjacent the leg 5 to the end that the free end ofthe reduced portion of the leg extension 'i will seat the leg 5 to the end which the detent ivcan be rotated so that the l, and materials may be resorted to without dej parting from the spirit and scope of the invention @as claimed hereinafter.

Having described the invention what is claimed square, a detachable leg extension, said leg eX- `tension being provided with a reduced end portion adaptedto extend parallel to and match one leg portion of the square, the other leg portion ofthe square having a recess in its end portion adjacent the matchedl leg portion for receiving the free end of the reduced portion of the leg extension, securing means between the free end portion ofthe reduced portion of the vleg extension and the square at the recess, and securing means between the free end portion of the matched leg portion of the'square and the leg extension.

2. A geometrical instrument4 comprising a e square, a detachableleg extension, said leg extension being provided with a reduced end portion adapted to extend parallel to and match one leg portion of the Square,v the other leg portion of the square having a recess in its end portion adjacent the matched leg portion for receiving i the free end of the reduced endk portion of the f leg extension, securing meansbetween the free end Vportion of the reduced portion of the leg extension and the square at the recess, and securing means between the free end portion of the matched leg portion of the square and the leg extension, the reduced portion' of the leg extension defining a shoulder between itself and the extension proper, the free end of the matched leg of the square being formed with an opening,

and a lug on the shoulder for engaging into and` latching the matched leg portion of the square f with the leg extension when the free end of the reduced portion of the leg extension is securedto the square at the recess. c

JOI-IN K. BARNS. 

